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Objective: To determine whether measures of maternal lean mass, fat reserves, or a combination of both best predict the various measures of newborn size at birth., Methods: The population consisted of 1205 multiparous, predominantly black women at high risk for fetal growth retardation, who delivered at term at the University of Alabama at Birmingham. Maternal body mass index (BMI) was calculated using the reported pre-pregnancy weight. Maternal anthropometric measurements taken at mid-pregnancy included skinfold thicknesses, lean body mass, and mid-arm, calf, and wrist circumferences. Weight and 11 other neonatal measurements were made within 24 hours of birth and related to various maternal anthropometric measurements., Results: Reported maternal pre-pregnancy weight was the best predictor of all neonatal size measures except for the neonatal skinfold thicknesses, which were better predicted by the pre-pregnancy BMI. For example, the range between the tenth and 90th percentiles of maternal pre-pregnancy weight (46.3-86.4 kg) was associated with 295 g birth weight compared to only 188 g birth weight for a measure of lean body mass., Conclusion: Most maternal anthropometric measurements were significantly associated with most neonatal measurements. However, for nearly every neonatal measurement considered, the maternal pre-pregnancy weight was the best predictor.

Objective: To summarize existing data about the effectiveness of bed rest when used to improve various pregnancy outcomes and to determine how often bed rest is used and the cost associated with its use., Data Sources: We used the MEDLINE data base to search for all English language papers evaluating the effectiveness of bed rest in pregnancy. We also reviewed a number of textbooks and the 1988 National Infant Mortality Survey., Methods of Study Selection: We reviewed these sources for recommendations about using bed rest in various obstetric conditions. We used the 1988 National Infant Mortality Survey to determine how often bed rest was used either to prevent or to treat various obstetric conditions and estimated the costs associated with its use., Data Extraction and Synthesis: Bed rest is used in nearly 20% of all pregnancies to prevent or treat a wide variety of conditions, including spontaneous abortion, preterm labor, fetal growth retardation, edema, chronic hypertension, and preeclampsia. There is little evidence of effectiveness. The estimated costs associated with bed rest, including hospitalization, lost wages, and lost domestic productivity, range from more than $250 million to billions of dollars per year., Conclusions: Bed rest is used extensively to treat a wide variety of pregnancy conditions, at substantial cost but with little proof of effectiveness. We recommend that because this intervention has failed the test of effectiveness, its use during pregnancy should be curtailed unless randomized trials demonstrate improvement in a specific outcome.

Objective: To perform a decision analysis to understand better the implications of 19 potential group B streptococcus screening and treatment strategies., Methods: We searched the literature to locate appropriate articles from which to derive probability estimates. Using decision analysis, we determined the likely outcomes of 19 group B streptococcus screening and treatment strategies and focused on three main outcomes: 1) number of expected cases of early-onset neonatal group B streptococcal sepsis, 2) percentage of gravidas treated with intrapartum antibiotics, and 3) total costs., Results: The strategy recently recommended by two committees of the American Academy of Pediatrics (universal 28-week maternal rectovaginal group B streptococcal culture and treatment of culture-positive, high-risk patients in labor) is among the least effective at reducing neonatal sepsis and the most costly. Strategies based on the currently available rapid streptococcus identification tests are ineffective at reducing neonatal sepsis and are costly. Three strategies outperform the rest: 1) Universal intrapartum maternal antibiotic treatment is the most effective strategy in reducing early-onset neonatal group B streptococcal sepsis (6% of expected) and is also the least costly; 2) intrapartum treatment based solely on risk factors (recently endorsed by ACOG) lowers the rate of neonatal sepsis to 31% of expected with an 18% maternal treatment rate and low total costs; and 3) universal 36-week maternal culture, and treatment of all patients experiencing preterm birth and all culture-positive patients results in 14% of expected neonatal sepsis, with a 27% maternal treatment rate and low total costs., Conclusion: Given the present state of knowledge, three strategies emerge from this decision analysis as most optimal for the prevention of early-onset neonatal group B streptococcal sepsis: universal treatment, treatment based on risk factors, and treatment based on preterm delivery and 36-week culture status.

Objective: We explored the relationships among measures of psychosocial well-being, maternal size, and smoking in predicting infant size at birth., Methods: Participants in this population-based cohort study were drawn from public health prenatal clinics in Jefferson County, Alabama during 1985-1988. Para 1 and 2 women were screened for 11 risk factors for low birth weight, including small stature, a previous low birth weight infant, and smoking., Results: Poor scores on five of six psychosocial scales, as well as on a combined profile, were associated with a significantly higher relative risk of fetal growth retardation (FGR) only in thinner women, defined as having a body mass index less than the median (relative risk [RR] 2.11, 95% confidence interval [CI] 1.47, 3.04). A significant association between the psychosocial profile and birth weight was demonstrated for thin women in a multivariate analysis adjusting for gestational age, race, infant sex, and smoking (P = .0003). The relationship remained significant when hypertension, alcohol and drug use, and weight gain were added to the model (P = .003). In women with a body mass index above the median, a poor psychosocial profile showed little association with FGR (RR 1.20, 95% CI 0.73, 1.98) and did not have a significant association with birth weight. A poor profile had a greater association with FGR in non-smokers (RR 2.04, 95% CI 1.29, 3.22) than in smokers (RR 1.4, 95% CI 0.95, 2.06)., Conclusions: Greater pre-pregnancy weight for height appears to protect against the adverse effects of a poor psychosocial profile in a population of poor, primarily black women. In thinner women, both smoking and a poor psychosocial profile were associated with a substantially increased rate of FGR, indicating a subgroup of women who may receive greater benefits from intervention programs.

Serum folate levels were measured at 30 weeks' gestational age in 289 pregnant women, each of whom had been provided with folate supplementation at enrollment in prenatal care. There was a significant association between low serum folate levels and fetal growth retardation. High folate levels were most likely explained by recent folic acid intake. Therefore, we were concerned that the decreased fetal growth associated with low folate levels may have been related to a combination of psychological and behavioral characteristics for which low serum folate levels were only a surrogate measure. A profile of maternal psychosocial status was created, which included measures of depression, anxiety, self-esteem, mastery, stress, and social support. Poorer psychological scores were significantly related to lower serum folate levels. However, in women with both good and poor psychosocial scores, high folate levels were significantly associated with increased birth weight, a relationship that persisted even after adjusting for maternal race, body mass index, smoking, history of a low birth weight infant, and infant gender. Our findings suggest that women with good psychosocial scores are more likely to take folate, but that the use of folate itself is related to a lower risk of fetal growth retardation and increased birth weight.

The effect of a previous low birth weight birth (less than 2750 g) was examined using a series of regression analyses. Effects on birth weight were partitioned into those associated with preterm delivery (128 g) and term delivery (178 g). Among term births, a mean difference of 107 g was associated with a previous birth of less than 2750 g, even after controlling for other risk factors including smoking, drug and alcohol use, maternal race, size, and hypertension. The pattern of measurements seen after a previous birth of less than 2750 g included significantly smaller head, chest, abdomen, arm, and thigh circumferences, but an insignificant impact on skinfold thicknesses and no significant effect on length measurements.

The mean birth weight of black infants is consistently less than that of white infants. In 1518 low-income multiparous women, the mean difference in singleton births was 171 g, of which 38 g was partitioned to preterm births and another 35 g reflected lower gestational ages in term births. A series of regression analyses were used to determine the effect of black race on various newborn measurements in 1205 term newborns, adjusting for other known risk factors. In this model, black race accounted for a mean decrease of 148 g in weight and 0.52 cm in length. There were also significant decreases in mean head (0.44 cm), chest (0.66 cm), and abdominal (0.56 cm) circumferences. Arm and leg lengths were not different, but black arm circumferences (0.14 cm) were significantly larger. Triceps and thigh skin fold measurements were not statistically different, but black subscapular skin fold values were significantly smaller (0.17 mm). The ponderal index in blacks was significantly less than in whites. These data suggest that in this population, intrinsic and/or extrinsic factors associated with race account for most smaller black newborn measurements and for much of the racial difference in birth weight.

Maternal serum alpha 2-macroglobulin levels were measured twice, at approximately 18 and 30 weeks' gestation, in 289 pregnant women who later delivered at or after 37 weeks. Levels were elevated as early as 18 weeks' gestation in women destined to have a growth-retarded infant, and this elevation persisted through 30 weeks' gestational age. Furthermore, levels were higher in white women than black, in smokers than in non-smokers, and in thin than in heavier women. When the effect of alpha 2-macroglobulin on birth weight was evaluated in a multiple regression analysis adjusting for gestational age, race, body size, smoking, fetal sex, and a history of a low birth weight infant, high alpha 2-macroglobulin levels were associated with a statistically significant decrease in birth weight. The effect was greater in women who smoked. This relationship did not appear to be associated with differences in serum zinc or hematocrit levels.

The relationship between maternal hematocrit and pregnancy outcome at various times in pregnancy was studied in 17,149 iron- and folate-supplemented pregnant women. On univariate analysis, early-pregnancy hematocrits below 37% were associated with preterm delivery. However, this relationship was not confirmed by multivariate analysis controlling for other risk factors. On both univariate and multivariate analyses, both early and later in pregnancy, hematocrits above 40% were associated with preterm delivery. In every gestational time period, at least part of the excess of preterm births was explained by an increase in indicated preterm deliveries. In both early and late pregnancy, and in both the univariate and multivariate analyses, only high hematocrits were associated with fetal growth retardation. The strongest association (odds ratio above 2) between high hematocrit and both fetal growth retardation and preterm delivery occurred with hematocrits at or above 43% at 31-34 weeks' gestation.

Birth weight-specific fetal death rates were evaluated for Alabama for the years 1974-1983. The fetal death rate for the total low birth weight group improved less than 20% during the decade, whereas the fetal death rate for the 2500-3999-g birth weight group improved 40%, and the fetal death rate for the group of 4000 g or more improved 71%. By 1983, 76% of all stillbirths weighed less than 2500 g, compared with 66% in 1974. In contrast, in both years, only about 7% of live births weighed less than 2500 g. This study suggests that increased reporting of stillbirths of less than 500 g has contributed to the recent apparent lack of improvement in stillbirth rates in Alabama.